ExplanationUse two separate lines in a W = RT chart, one for Wendy and one for Miguel, to calculate their respective rates. Building 1 birdhouse equals doing 1 unit of work:
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Thus, Wendy’s rate is \(\frac{1}{15}\) birdhouses per hour, and Miguel’s rate is \(\frac{1}{10}\)birdhouses per hour. Since Wendy and Miguel are working together, add their rates:
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Now solve for t by first combining the fractions:
\(1=(\frac{1}{15}+\frac{1}{10})t\)
\(1=(\frac{5}{30})t\)
\(t=6\)